Telkom stole my data

I signed up for a 10gig anytime with Telkom with a pocket size wifi device, last month. I only use the device for my watsup message on my tablet and there was no problems experienced on the 1st month. Today when I turned my device on, I had used up 7gig according to telkom wifi, and when I turned my device on again around 3pm, the device showed I had used up 9.8Gigs, I was shocked because I only received 4 messages on my watsup today, I called Telkom to complain and a consultant named Tshego told me according to their systems there was a data usage of 3gigs between 11am and 14:50, I told her I didn't use that much data, as I only use the device for watsup messages on my tablet, she told me on their side, they have no way of telling which devices used the data and they can't take my word for it. I feel cheated, ****** of my data, shocked and out of words. I can confirm that Telkom stole my data.